The present invention relates to improvements in methods of laying and in combinations of parts for confining data cables, electrical conductors and the like in existing underground pathways including those defined by sewage pipes, water pipes, gas pipes and others.
In many communities, including large cities as well as smaller inhabited developments, the pipes (this term is utilized generically and embraces all or practically all types of underground as well as many aboveground passageways and conduits) are already utilized as a means for accommodating, confining, shielding and supporting information-, current- and/or signal-transmitting cables in the form of glass fibers, metallic wire-like conductors and others. An advantage of such mode of confining and shielding cables (this term will be employed hereinafter to cover all kinds of wire-like, filamentary and other components which must be laid to and/or from houses, apartment buildings, office buildings, factories, shops and other establishments in order to receive and/or to transmit information, energy, fluid, signals and the like) in pipes is that the ground need not be dug up by tools and/or by machines in order to gain access to the confined cables which are laid in underground pipes.
Access to underground pipes is required at rather frequent intervals for any one of a large variety of reasons such as to repair damaged pipes, to lay additional cables, to remove damaged and/or no longer needed cables, to establish branches of cables leading into previously unoccupied pipes, to clean the pipes, to reinforce selected portions of or entire pipes, and many others. One of very frequent reasons for the need to gain access to underground pipes is to clean and/or rehabilitate pipes which are confined in the ground below roads, streets, plazas, buildings, parks, playgrounds or the like and are in use for long periods of time, e.g., for 30 years, 50 years or even longer.
One presently preferred mode of restoring the usefulness of antiquated pipes is to provide the internal surfaces of such pipes with liners of a plastic or other suitable material. Unless a complete renovation of underground piping is unavoidable due to the condition of existing pipes, the utilization of liners can prolong the useful lives of internally pressurized or open underground pipes for many years, e.g., for many decades. Therefore, and since the utilization of robots and similar equipment renders it possible to clean existing pipes, to introduce cables into existing pipes and/or to provide existing pipes with suitable liners, it is not necessary to dig up the land above the buried pipes with thus achieved additional savings in time, cost and inconvenience to persons and/or vehicles on the ground above the buried pipes. Another advantage of the just outlined modes of renovating underground pipes is that, in many or most instances, damaged or antiquated underground pipes are frequently found in those sections of cities, towns and other localities which are impoverished so that, quite frequently, they would be last to be assigned extensive repair work involving underground piping if such repair work is expected to be highly expensive.
Certain known restoration methods, namely the so-called hose and liner methods, involve the laying of liners by pulling a liner into a damaged pipe or by turning the liner inside out in the pipe. The liner can contain various tissues and/or foils and/or other constituents and is saturated with a suitable hardenable or settable resin or the like prior to being pressed against the internal surface of the freshly cleaned or non-cleaned pipe by a pressurized liquid or by a compressed gaseous fluid. Once the resin sets, the liner constitutes a new (inner) pipe within the old pipe. As a rule, the new pipe is fluidtight and it can enhance or reestablish the structural integrity of the thus renovated original pipe.
Branches of existing pipes, too, can be renovated (such as reinforced) without difficulty by resorting to the aforediscussed hose and liner method so that the thus renovated pipes and/or their branches are ready for further use for many years with a negligible or minimal reduction of their inner diameters. The just described renovation or restoring work can be carried out regardless of the overall length and layout of existing underground pipes because certain parts of such underground networks are always accessible by way of existing removable or openable covers or the like. Thus, the provision of adits to and exits from existing pipes need not involve any digging up of streets or the like, even for short periods of time.
Published German patent application Serial No. 197 01 787 A1 of Hecht proposes the utilization of a robot for the installation of clamps within an underground sewage pipe and to employ such clamps to secure protective tubing for the confinement of data cables. A drawback of such proposal is that the thus installed protective tubing is likely to be damaged during periodic cleaning of the sewage pipes. Moreover, the tubes which are suspended in the sewage pipes prevent subsequent resort to numerous types of repair work, e.g., the utilization of cleaning robots which are used to establish passages in clogged pipes by resorting to high-pressure water jets or to mechanical means, such as milling cutters. Moreover, debris and other impurities are likely to be intercepted by the suspended tubes and/or by their clamps which can result in rapid clogging of the sewage pipes.
U.S. Pat. No. 5,305,798 (granted Apr. 26, 1994 to Driver) discloses a so-called two-wall leakage detection system for an underground pipe. A detection device, together with a body of absorbent material, is installed between the internal surface of a sewage pipe and the external surface of an impervious tubular liner. The detection device is contacted by moisture in the event of a leak in the underground pipe and/or in the liner. This is ensured by the provision of the aforementioned body of absorbent material which at least partially surrounds the detection device and must remain absorbent if it is to serve its purpose. On the other hand, confined data cables should be installed in a sewage pipe or the like in such a way that they remain out of contact with the gaseous and/or hydraulic fluids which are being conveyed in and/or which penetrate into the pipe due to a leak and/or other damage to the pipe.
Published Japanese patent application Serial No. 02221732 (filed Aug. 22, 1990 by Moriyuki) proposes to establish connections between first optical fiber cables in a manhole and second optical fiber cables by providing a junction box at the inner side of the pivotable lid for the manhole. The connections between the two sets of cables can be established or interrupted while the junction box is accessible, i.e., while the lid is pivoted to a position in which the box at its inner side is accessible from the outside.
Published German patent application Serial No. 42 03 718 A of ANT Nachrichtentechnik GmbH (published Aug. 8, 1993) proposes to install cables in the uppermost portions of underground sewage, water or other pipes so that the cables are contacted by a liquid only when the pipes are filled.
Published German patent application Serial No. 197 34 274 A1 (filed by Siemens A G and published Feb. 11, 1999) discloses discrete fiberoptical cables or groups of coherent fiberoptical cables which are led into underground pipes and thence into individual dwellings. This publication fails to propose the utilization of a liner which could urge the cable or cables against the internal surface of an underground pipe.
An object of the present invention is to provide a novel and improved method of ensuring that the cable or cables which is or which are confined in a sewage pipe or the like is or are invariably protected against mechanical or chemical damage during and subsequent to laying.
Another object of the invention is to provide an arrangement for the transmission of data through a communal sewage pipe system with at least one sewage pipe and at least one service duct wherein the cable or cables can be communicatively connected with consumers"" data cables in a reliable manner.
A further object of the invention is to provide a method which renders it possible to shield confined cables from undesirable mechanical and/or other influences in sewage pipes or the like in several ways.
An additional object of the invention is to provide a method which can be practiced simultaneously with or independently of repair work upon sewage pipes or the like without necessitating any excavation work.
Still another object of the invention is to provide a method which can be resorted to for reliable and long-lasting confinement of cables in underground pipes irrespective of the purpose of such pipes, i.e., regardless of the nature, pressure and/or other parameters of the fluid or fluids which is or are being conveyed in the pipes.
A further object of the invention is to provide a novel and improved combination of an underground pipe and one or more cables in the pipe.
Another object of the invention is to provide a pipe-cable combination which can be established prior or subsequent to burying of the pipe below the ground level, in the wall of a building or in other hard-to-reach locations.
One feature of the present invention resides in the provision of a method of confining at least one cable (e.g., an electric conductor or an optical fiber cable) in an elongated underground pipe (such as a sewage pipe or a water pipe) having an internal surface (e.g., a cylindrical internal surface). The improved method comprises the steps of confining the at least one cable in a body of a settable material, inserting the body into the pipe prior to setting of the material of such body, introducing into the pipe a deformable tubular liner, expanding the liner from within to thus urge the body against the internal surface of the pipe, and causing the body to set.
The method can further comprise the step of withdrawing the liner from the pipe upon completed setting of the body.
In accordance with a presently preferred feature of the improved method, the step of causing the body to set further includes bonding the body to the internal surface (particularly to a portion of the internal surface) of the pipe.
The body can constitute an elongated strip, and the inserting step can include causing the strip to extend lengthwise of the pipe.
The expanding step can include causing the liner to urge one side of the strip flush against the internal surface of the pipe.
The method can further comprise the step of surrounding the at least one cable by a protective tube or envelope prior to the confining step. The at least one cable can be introduced into the protective envelope prior or subsequent to introduction of the envelope into the body. For example, the at least one protective tube or envelope can be embedded in the body prior to the confining step, and the confining step can include inserting the at least one cable into the at least one tube.
If the at least one cable is a conductor of electric current, the step of causing the body to set can include electrically heating the at least one cable to thus heat a body which consists of or contains a thermosetting material.
The introducing step can include introducing into the pipe a deformable tubular liner which contains at least one reinforcing insert and/or at least one foil.
The confining step can include employing at least one cable having at least one terminal extending beyond an end portion of the pipe upon setting of the body in the interior of the pipe, and such method can further comprise the step of introducing the at least one terminal into a data box or into a second pipe. Still further, such method can comprise the steps of confining the at least one cable in a protective tube or envelope and connecting the at least one cable with at least one additional cable in the interior of the data box. Still further, such method can include the step of confining a portion of the envelope or tube in a suitable enclosure (e.g., in an annular enclosure) for the data box. Such portion of the envelope can contain a small, reasonable or even large supply of the at least one cable.
The just outlined method can further comprise the step of providing at least one of the pipes (i.e., the elongated underground pipe and/or the second pipe) with a recess or channel and confining a portion of the at least one terminal in the recess. Such method can further include providing the at least one pipe with a protective member (such as a collar) for the at least one terminal of the at least one cable. The collar can be affixed to the at least one pipe.
Still further, the method can comprise the step of confining the aforementioned data box in a manhole having a cover which can be pivoted to open position or lifted off the major part of the manhole to afford access to the data box.
The inserting step can include locating the body at the apex of the at least one pipe.
If the liner is to be withdrawn from the pipe upon completed setting of the body, such liner can be made of rubber or another suitable resilient material.
Another feature of the present invention resides in the provision of a combination of parts which includes an elongated pipe defining a path for the confinement and transport of flowable substances (such as sewage or water) and having an internal surface which surrounds the path, a body which contains a hardened resin or another hardenable material and abuts and adheres to a portion of the internal surface of the pipe, and at least one cable (e.g., a fiber optic cable or a conductor of electric current) which is confined in the body.
The improved combination can further comprise a tubular liner having an external surface which abuts in part the internal surface of the pipe and in part the internal surface of the body. Such liner can contain a hardened material and can be permanently embedded in the pipe.
The aforementioned body can include an elongated band or strip which extends lengthwise of the pipe and has an external surface adhering to the internal surface of the pipe.
The at least one cable can constitute a cable made of copper or another metallic material.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved combination of parts itself, however, both as to its construction and the modes of assembling, installing and utilizing the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.